In various packages or cartridges now in use for webs of photographic film and paper, the web is wound on a spool or core, with or without flanges, and is disposed within a magazine which totally surrounds the web and protects it from light and other damaging effects. One end of the web is normally secured to the core or spool center and the other end extends out of the magazine through a slot therein. The other end is fastened to the surface of the cartridge and is released therefrom for insertion into a camera or the like. It has been found that there is a tendency for the web in such cartridges to unwind during handling and shipping. Inasmuch as the inner end of the web is connected to the core or the spool center and the outer end is normally secured to the outer surface of the cartridge, the web acts as a released clockspring, turning the spool as it unwinds. Such clockspringing can result in scratching of the surface of adjacent web convolutions causing a deterioration in the quality of the image that may be recorded thereon. In other instances, the web can clockspring outwardly to the extent that the outer convolution of web jams against the inner surface of the cartridge making subsequent unreeling of the web difficult or impossible. In those situations in which the outer end of the web is not fastened to the surface of the cartridge or is inadvertently released from the cartridge surface, the clockspringing can cause the outer end of the web to be pulled back through the slot into the cartridge resulting in a cartridge that is completely unusable.
Various attempts have been made in providing anti-clockspringing apparatus to prevent unwinding of the web in cartridges. For example, a core-locking device for a web dispensing cassette is disclosed and published as item No. 16352 in the November 1977 issue of Research Disclosure. In this core-locking apparatus, a web winding core is provided with a slotted end, and a core-locking member is provided that is captive and slideable (but yet light-tight) in one of two end caps of the cassette. In U.S. Pat. No. 3,784,001 which issued to Bushnell et al. on Jan. 8, 1974, a film cartridge is disclosed in which clockspringing of a roll of film is prevented by providing a flangeable connector between the core and a portion of the cartridge which has sufficient strength to prevent the core from rotating during shipping but which will break as the film is withdrawn from the cartridge, permitting the core to rotate. In U.S. Pat. No. 4,210,296, which issued to Frechette on July 1, 1980, a ribbon cartridge with an integral anti-spool rotation device is disclosed. The anti-spool rotation device comprises an axially movable core insert connected to the cartridge wall by flexible bridges or arms. The core insert is manually pressed into the open end of the core to frictionally hold the core against rotation. Upon mounting the cartridge in a machine, a post thereon will axially push the core insert out of frictional engagement with the spool core thereby allowing free rotation of the supply spool. In still another prior art reference, U.S. Pat. No. 3,613,876, which issued to Kohler et al. on Oct. 19, 1971, an anti-clockspring device is disclosed for a film cartridge in which one or more spot welds is provided between the surface of the core and the end of the hub. The spot weld has sufficient strength to prevent the core from rotating during shipping, but will break as the film is withdrawn from the cartridge, permitting the core to rotate. It is also known in the prior art to prevent clockspringing of a wound roll of web material within a cartridge by providing aligned notches in outer surfaces of the core end and cartridge wall and placing a rubber band around the entire cartridge with the band nesting in the notches. Although the various prior art attempts at solving the anti-clockspringing problem in web cartridges have had various degrees of success, the need still exists for a simple, reliable and economical anti-clockspringing apparatus and method.
Therefor an object of the present invention is to provide an anti-clockspringing apparatus and method that is of simple design and construction, thoroughly efficient and reliable in operation, and economical to manufacture.